1. Field of the Invention
The present invention relates to a terminal box device. It relates in particular to a terminal box device which can be easily electrically connected to a solar panel, such as a solar panel which can be installed on a roof (or the like) of a building for the generation of electricity. The invention further relates to an assembly including a terminal box device and a solar panel.
2. Description of the Prior Art
As illustrated in FIG. 8, it is known to provide a terminal box 1 on the rear surface of a solar panel 4. The solar panel 4 has a large number of solar cells 2 (designated collectively by the reference numeral 3). The solar cells 2 are electrically connected in series with one another. The solar cells are partitioned into groups, and each group of solar cells is connected in parallel with a respective bypassing rectification element (diode) accommodated inside the terminal box 1. The bypassing rectification elements ensure that even if a certain solar cell enters a state in which it ceases to conduct (e.g. because the solar cell is in the shade), it does not prevent the solar panel 4 generating a voltage (by the other groups of solar cells) because the respective bypassing rectification element shorts it out.
As shown in FIGS. 9 and 10, the terminal box 1 includes a terminal box body unit 6 and a plate-shaped cover 7 installed on the body unit 6. The body unit 6 is formed of a resin such as a plastics material. The body unit 6 includes a casing 8 having an upper surface (as viewed on FIG. 8) which defines an upwardly facing recess, and a bottom surface 16 which is rectangular. Four wiring holes 10a, 10b, 10c, 10d are arranged in a row on the bottom surface 16. Four terminals 11a, 11b, 11c, and 11d are arranged in a row at positions corresponding to the positions of the holes 11a, 10b, 10c, 10d. The terminals 11a, 11b, 11c, 11d are fixed to the casing 8 by respective screws 12a, 12b, 12c, 12d. Panel connection cables 5a and 5d are fixed to the terminals 11a and 11d, positioned at either end of the row of terminals 11a-11d, by respective screws 12a and 12d. The panel connection cables 5a and 5d lead out of the body unit 6 through two wiring holes 14a and 14d, respectively formed on a side surface 13 of the casing 8. Three bypass diodes 15 are soldered pairwise between the terminals 11a-11d, such that a respective bypass diode 15 is interposed between the terminals 11a and 11b, 11b and 11c, and 11c and 11d. 
The terminal box body unit 6 is installed on the solar panel 4 as follows. The rear surface 16 of the casing 8 of the terminal box body unit 6 is positioned against a rear surface 17 of the solar panel 4; the ends of two output leads 18a and 18d (connected with cells 3 of the solar panel 4) provided on the rear surface 17 of the solar panel 4 are introduced into the casing 8 through the respective wiring holes 10a and 10d. Then, the two output leads 18a and 18d are soldered to the terminals 11a and 11d. To make the body unit waterproof and moisture-proof, to promote heat release and to prevent moisture condensation, the casing 8 is filled with silicone 19 such that the silicone 19 covers the bypass diodes 15, the terminals 11a-11d, and the sides of one end of each of the cables 5a and 5d. Finally, the cover 7 is installed on the casing 8 to cover the recess in the casing 8.
As shown in FIG. 11, the panel connection cable 5a of a terminal box 1 installed on a first solar panel 4 can be connected to the panel connection cable 5d of a terminal box 1 installed on another solar panel. In this manner, it is possible to connect in series a plurality of solar panels 4 which are arranged in a row on a roof or the like.
As shown in FIG. 12, to extract electric power from the solar panels 4, the solar panels 4 may be electrically connected in series with one another to construct a photo-voltaic system 21; and the solar panels connected with one another in series are connected with an inverter or a connection box 20 to extract electric power as alternating current.
The conventional terminal box 1 for a solar panel 4 is manufactured by a terminal box manufacturer without installing the cover 7 on the terminal box body unit 6. A solar panel assembly manufacturer installs the terminal box body unit 6 on the solar panel 4, fills the casing 8 with silicone, and finally installs the cover 7 on the terminal box body unit 6. In this manner, the terminal box 1 for the solar panel 4 is completed.
As described above, in installing the terminal box 1 on the solar panel 4, it is necessary for the manufacturer of the solar panel to fill casing 8 with the silicone 19. This is done when the terminal box body unit 6 is already installed on the solar panel 4. Thus, an operator must perform a difficult silicone-filling operation including many steps. This results in poor operation efficiency, and so prevents the manufacturing cost of the photo-voltaic system from being reduced.
Further, if a bypass diode 15 of the terminal box 1 installed on the solar panel 4 is damaged during use, the bypass diode 15 cannot be replaced individually on the spot. Instead the whole of the terminal box 1 and solar panel 4 must be replaced with a new terminal box 1 and a new solar panel 4. This increases maintenance cost, and also prevents the manufacturing cost of the photo-voltaic system from being reduced.
The present invention has been made in view of the above-described problems. The present invention aims to provide a new and useful terminal box device for a solar panel, and in particular an inexpensive terminal box device which can be easily installed on a solar panel while still being adequately waterproof, and which can be maintained at reduced cost.
In general terms, the present invention proposes that a terminal box has a body unit and a cover unit which can be fastened to each other. The cover unit contains the rectification elements and electrical connections which lead outside the terminal box. It is filled with a filler. The body unit can be mounted on the solar panel and provides connections to the solar cells of the solar panel.
Specifically, in a first aspect the present invention provides a terminal box device for a solar panel, comprising a body unit and a cover unit;
said body unit comprising:
a casing, the casing defining a recess and having an attachment surface for attachment to the solar panel, and
a plurality of terminals for connection to photoelectric conversion elements of a solar panel, said terminals being fixedly accommodated in said casing;
said cover unit comprising:
a cover member defining a chamber,
a plurality of terminal members, said terminal members being fixedly accommodated in said chamber,
a plurality of cables, said cables being connected with respective said terminal members,
a plurality of bypassing rectification elements, said bypassing rectification elements each being electrically connected to a respective pair of said terminal members, and
a filler, the filler in said chamber which covers said bypassing rectification elements, a part of each of said terminal member being exposed;
said cover unit being removably fastenable in a location on said body unit in which said recess faces said chamber; and
said terminal members and said terminals being arranged in corresponding respective positions, whereby, when said cover unit is fastened in said location on said body unit, said terminal members and said terminals are electrically connected with each other.
Due to this construction, a terminal box manufacturer can manufacture the body unit and the cover unit, including the step of filling the cover unit with filler, and deliver them to a manufacturer of solar panels. The solar manufacturer connects the output leads of a solar panel with the respective terminals of the body unit, and installs the cover unit on the body unit. Thus, the assembly process if simplified, by comparison to the known assembly process described above.
Furthermore, if a bypassing rectification element of the terminal box device is damaged during use, the terminal box device can be repaired by replacing the cover unit only. Thus, unlike the known assembly described above, there is no need to replace the solar panel.
Preferably, said plurality of bypassing rectification elements are electrically connected to a respective pair of said terminal members which are adjacent.
Preferably, a plurality of wiring holes are formed in said attachment surface in positions corresponding to the positions of respective said terminals;
and said body unit includes a plurality of waterproof walls, each of said waterproof walls surrounding a respective one of said terminals and a respective one of said wiring holes, each of said waterproof walls having an upper surface which, when said cover unit is fastened in said location to the body unit, closely contacts a surface of said filler, whereby a watertight connection is made. The waterproof walls effectively prevent water from penetrating into the bypassing rectification elements.
Preferably, a waterproof seal is provided on at least one of (i) a peripheral part of said casing encircling said recess and (ii) a peripheral part of said cover member encircling said chamber, whereby, when said cover unit is fastened in said location to the body unit, said waterproof seal is interposed between said cover member and said body unit and constitutes a waterproof seal encircling said recess and said chamber.
Preferably, each of the terminal members has a fixing portion fixed to an inner surface of said cover member and covered with said filler, and a connection portion projecting out of said filler; and
each of said terminals has a fixing portion fixed to an inner part of said recess, and a connection portion projecting from said casing,
said connection portion of each terminal member being electrically connected to the connection portion of the respective said terminal when said cover unit is fastened in said location to the body unit.
Preferably, the connecting portion of each terminal includes erect portions and when said cover is fastened in said location to the body unit, the connection portion of each terminal member is received in a gap between said erect portions of said respective terminal. Thus, the connection portion of each terminal is connected to the connection portion of the respective terminal member merely by installing the cover unit on the body unit. Therefore, assembly is very much simplified by comparison to the known terminal box described above.
In a second aspect, the present invention provides an assembly comprising a terminal box device and a solar panel,
the solar panel having at least one photoelectric conversion element;
the terminal box device comprising a body unit and a cover unit;
said body unit comprising:
a casing, the casing defining a recess and having an attachment surface attached to the solar panel, and
a plurality of terminals electrically connected to said photoelectric conversion elements, said terminals being fixedly accommodated in said casing;
said cover unit comprising:
a cover member defining a chamber,
a plurality of terminal members, said terminal members being fixedly accommodated in said chamber,
a plurality of panel connection cables, said panel connection cables being connected with respective said terminal members and extending out of said cover member,
a plurality of bypassing rectification elements, said bypassing rectification elements each being electrically connected to a respective adjacent pair of said terminal members, and
a filler, said filler filling said chamber and covering said bypassing rectification elements, a part of each of said terminal member being exposed;
said cover unit being removably fastened in a location on said body unit in which said recess faces said chamber; and
said terminal members and said terminals being arranged in corresponding respective positions, whereby, when said cover unit is fastened in said location on said body unit, said terminal members and said terminals are electrically connected with each other.